Case–Control Study of Long COVID, Sapporo, Japan

• Published in: Emerging Infectious Diseases Vol. 29; no. 5; pp. 956 - 966
• Main Authors: Asakura, Toshiaki, Kimura, Takashi, Kurotori, Isaku, Kenichi, Katabami, Hori, Miyuki, Hosogawa, Mariko, Saijo, Masayuki, Nakanishi, Kaori, Iso, Hiroyasu, Tamakoshi, Akiko
• Format: Journal Article
• Language: English
• Published: United States Centers for Disease Control and Prevention (CDC) 01.05.2023; U.S. National Center for Infectious Diseases; Centers for Disease Control and Prevention
• Subjects: Analysis; Case-Control Studies; Case–Control Study of Long COVID, Sapporo, Japan; Cohort analysis; coronavirus disease; COVID-19; COVID-19 - epidemiology; COVID-19 vaccines; Cross-Sectional Studies; Fog; Humans; Illnesses; Immunization; Infections; Infectious and parasitic diseases; Japan; Japan - epidemiology; Long COVID; Medical research; Medical tests; Medicine; Menstruation; Patients; Post-Acute COVID-19 Syndrome; Public health; Questionnaires; R; RC109-216; respiratory infections; SARS; SARS-CoV-2; Severe acute respiratory syndrome coronavirus 2; Japan; COVID-19; SARS-CoV-2; viruses; severe acute respiratory syndrome coronavirus 2; Japan; post–COVID-19 condition; SARS; coronavirus; zoonoses; coronavirus disease; long COVID; respiratory infections
• ISSN: 1080-6040; 1080-6059; 1080-6059
• DOI: 10.3201/eid2905.221349

We conducted a cross-sectional survey among SARS-CoV-2-positive persons and negative controls in Sapporo, Japan, to clarify symptoms of long COVID. We collected responses from 8,018 participants, 3,694 case-patients and 3,672 controls. We calculated symptom prevalence for case-patients at 2-3, 4-6, 7-9, 10-12, and 13-18 months after illness onset. We used logistic regression, adjusted for age and sex, to estimate the odds ratio (OR) for each symptom and control reference. We calculated symptom prevalence by stratifying for disease severity, age, and sex. At 4-18 months from illness onset, ORs for anosmia, ageusia, dyspnea, alopecia, and brain fog were consistently >1, whereas ORs for common cold-like, gastrointestinal, and dermatologic symptoms were <1. Time trend ORs increased for diminished ability to concentrate, brain fog, sleep disturbance, eye symptoms, and tinnitus. Clinicians should focus on systemic, respiratory, and neuropsychiatric symptoms among long COVID patients.